Epigenetic Regulation of Juvenile Hormone

We recently showed that histone deacetylase 1 (HDAC1) plays an important role in juvenile hormone (JH) suppression of metamorphosis in the Tribolium castaneum. Here, we investigated the function of another class I HDAC member, HDAC3, and show that it plays a significant role in pupal development. Knockdown in the expression of HDAC3 gene affected development resulting in abnormally folded wings in pupae and adults. JH analog, hydroprene suppressed HDAC3 expression in the larvae. Knockdown of HDAC3 during the final instar larval stage induced the expression of genes coding for proteins involved in JH action. RNA-seq analysis from larvae injected with dsmalE or dsHDAC3 identified 741 differentially expressed genes. Several genes, including those coding for myosin-I heavy chain (Myosin 22), Shaven, and nuclear receptor corepressor 1 are identified as differentially expressed genes in HDAC3 knockdown larvae. An increase in histone H3 acetylation, specifically H3K9, H318, and H327, was detected in HDAC3 knockdown insects. In conclusion, HDAC3 affects the acetylation of histones, resulting in a change in chromatin status and expression of genes involved in numerous vital biological processes.